The Inoculation Fallacy: Why Early Enrichment Cannot Compensate for Poor Adult Environments

Abstract Early-life environmental enrichment (EE) is widely promoted as a route to building resilience and competence, yet these benefits rarely persist when adult environments lack opportunities for agency. Resilience and competence are behavioral properties of current reinforcement contingencies, not internal traits. Across species, early EE fails to compensate for adult environments that withdraw stimulus support or eliminate response–outcome contingencies, producing generalization decrement, extinction-driven behavioral collapse, and negative contrast. Early EE may enhance functional capacity, but positive animal welfare requires sustained agency in adulthood. Welfare strategies should therefore prioritize adult environments that provide reliable choice and instrumental control, with early EE playing a supportive rather than protective role.